He is building in the unstable desk.他正在加固那张不稳的桌子。

build in 使成为固定物,使成为组成部分（To construct or include as an integral part of）。Build-in也可以作为形容词，表示的含义相近。
　　例句：
　　There 's a build-in flashgun in this camera.
　　这架照相机有一个内置闪光灯。